degenhardt



March 17, 1964 c. J. DEGENHARDT 3 WARD LEONARD EMERGENCY STOP APPARATUS FOR STEEL MILLS Filed Jan. 15, 1962 2 Sheets-Sheet 1 INVENTOR. CARL J. DEGENHARD T Attorney M 1964 c. J. DEGENHARDT 3,125,713

WARD LEONARD EMERGENCY STOP APPARATUS FOR STEEL MILLS Filed Jan. 15, 1962 2 SheetsSheet 2 46C 468 52 1 I 4 24 --1-"T 28 30 ,8

| I Ll 46 46A 46B 46C 7 ##W J1 L2 INVENTOR. CARL J. DEGENHARDT A Horney United States Patent 3,125,713 WARD LEONARD EMERGENCY STOP APPARATUS FOR STEEL MILLS Carl J. Degenhardt, Pittsburgh, Pa., assignoito United States Steel Corporation, a corporation of New Jersey Filed Ian. 15, 1962, Ser. No. 166,298 6 Claims. (Cl. 318-158) This invention relates to emergency stop apparatus and more particularly to apparatus for quickly stopping the drive motor of a rolling mill. A rolling mill drive Oldlnarily includes a spindle having one end connected to the drive motor and the other end connected to the rolling mill roll through a universal coupling. This arrangement is necessary in order to permit the drive to function with changing spindle angles as the top work roll'is raised and lowered. When there is excessive scale on an ingot or slab as it enters the mill, slippage occurs between the work piece and roll which results in chattering and vibration with severe shock load. This may result in spindle breakage. If the spindle or any part of the connection breaks for this or any other reason, the spindle will whip and continued rotation will cause extensive mechanical damage to the spindle carrier, its supports, foundations, and other equipment in the immediate area. In most instances this damage resulted before the operator could shut down the mill.

It is therefore an object of my invention to provide apparatus for immediately stopping the drive motor when excessive vibration occurs in the connection between the motor and roll or when a break occurs in this connection.

This and other objects will be more apparent after referring to the following specification and attached drawings, in which:

FIGURE 1 is a side elevation showing a rolling mill drive with my invention incorporated therein;

FIGURE 2 is an enlarged view taken on the line IIII of FIGURE 1; 1

FIGURE 3 is an end view of FIGURE 2; and

FIGURE 4 is a schematic view showing the electrical wiring diagram utilized in my invention.

Referring more particularly to the drawings, reference numeral 2 indicates the upper roll of a roll mill stand and reference numeral 4 indicates the lower roll thereof. The rolls 2 and 4 are mounted in the usual housing which is unmounted for the purpose of simplicity. The roll 2 is connected through a universal coupling 6 to one end of a spindle 8 which is rotatably mounted in bearings 10 and 12. The other end of the spindle 8 is connected by means of a crab coupling 14 and coupling 16 through gearing 18 to a drive motor 20. The bearings 10 and 12 are supported by a spindle carrier 22. In like manner the roll 4 is connected by means of universal coupling 24, spindle 26, crab coupling 28 and coupling 36 through gearing 18 to drive motor 20. The spindle 26 is supported in bearings 32 and 34 which in turn are carried by hearing supports 36 and 38. The parts so far described are conventional and per se form no part of the present invention and it will be understood that separate motors may be provided for driving each of the spindles 8 and 26 rather than having a single motor for this purpose.

According to my invention I provide a hinge bar 40 adjacent each of the bearings 10, 12, 32 and 34. Since the arrangement is the same at each bearing, only one arrangement will be described in detail. As shown in FIGURE 2 one hinge bar 40 is pivotally mounted at 42 on the spindle carrier 22. The lower hinge bars 40 are pivotally mounted on hearing supports 36 and 38. The hinge bar 40 of FIGURE 2 is spaced a short distance from spindle 8 and carries a striker block 44 adjacent 3,125,713 Patented Mar. 17, 1964 ice the free end thereof. A limit switch 46 having an operating lever 46L is mounted on spindle carrier 22 with the lever arm 261. being arranged for operation by striking block 44.

The motor 24} is connected to the output of a direct current generator 48 having a field 48F. The limit switches 46, 46A, 46B, and 46C, one for each end of each or" the spindles 8 and 26, are connected in series with a relay coil 50 to power source L1 and L2. Relay coil 50 has normally open contacts 50C and 50C1 and normally closed contact 5002. A switch 52 controls flow of the current through the switches 46, 46A, 46B, and 46C. Contact 50C is arranged in series with a relay coil 54 which has a normally open contact 54C. The contact 54C is connected in series with relay coils 56 and 58 which are arranged in parallel with one another. Relay coil 56 has a normally open contact 56C and a normally closed contact 56C1 and relay coil 58 has a normally open contact 53C. The contacts 56C and 53C are connected in the circuit of field 48F. Contacts 50C1 and 56C1 are connected in series with each other through suicide relay coils 60 and 62 which are connected in parallel with each other. Coils 6i) and 62 have normally open contacts 66C and 62C, respectively, which are connected across field 48F to the output of generator 48. A generator voltage relay 64 is connected across the output busses 66 and 68 of generator 48. Relay coil 64 has a normally closed contact 64C which is connected in series with contact 50C2, contacts StlCZ and 64C being connected in parallel with contact 50C1. A relay coil 70 is connected in parallel with contact 5tiC2 and in series with contact 64C. Coil 70 has a normally open contact 7 M? which is connected across busses 66 and 68 in series with a horn '72 and a resistor 74. A signal light 76 and resistor 78 are connected in parallel with born 72 and resistor 74.

The operation of my device is as follows:

Under normal operation the spindles 8 and 26 rotate concentrically within their bearings, thus maintaining a gap between the spindles and the adjacent hinge bars 40. However, when a part of the connection between the drive motor and mill roll breaks, or when there is ex cessive vibration for any reason such as that mentioned above, the spindles start to whip or vibrate an amount suflicient to cause one or more of the striking blocks 44 to actuate its associated switch to open position. When this occurs, spindle contact relay coil 56 will be deenergized, thus opening its contacts 50C and StlCl and closing its contact 50C2. Opening of contact 50C deenergizes relay coil 54, thus opening its contact 54C. Opening of contact 54C deenergizes relay coils 56 and 58.

' Deenergization of coil 56 opens its contact 56C and closes its contact 56Cl. Deenergization of coil 58 opens its contact 58C. Opening of contacts 56C and 58C deenergizes field 48F so that the generator 48 voltage will gradually decrease and motor 20 will start to decelerate in normal manner. Opening of contact 50C1 prevents energization of coils 60 and 62 unless contacts 50C2 and 640 are closed. When the voltage across busses 66 and 68 drops to predetermined value, the voltage relay 64 will drop out and close its contact 64C. This energizes relay coils 6t), 62 and '70. Energization of coils 60 and 62 closes contacts 69C and 62C so as to apply reverse power circuit voltage to generator field 43F, thus rapidly returning the generator voltage to almost zero and holding it there. The control circuits are held in this condition until manual resetting of any open limit switch 46, 46A, 46B or 46C. Thus it is seen that the actuation of any one of the limit switches will rapidly bring the drive motor 20 to a stop so as to prevent or restrict damage to the equipment. It will be understood that usual protective relays, resistors and the like will be included in the control circuits; these not being shown since they are not pertinent to the present invention. The operation of my device has proved to be very successful in that no case of spindle breakage has occurred since it has been placed in operation, the motor being stopped before this can occur.

Proper operation of the generator voltage relay 64 is important, since the opening of a spindle limit switch when the relay 64 is not operating, may connect the generator field 43F into the suicide circuit at too high a voltage and cause insulation damage to the field and pos sibly additional damage tothe mechanical system. At low generator voltage, relay coil 64 will not operate to open its contact 64C so that, through the normally closed contact 64C, coil 70 is energized to close its contact 70C and complete circuits through horn 72 and light 76. However, at this low voltage no signal is given. As the voltage increases to the value at which relay 64 is set to operate, the contact 64C opens, thus deenergizing coil 70 and opening its contact 70C so that the signals 72 and 76 will not work. However, if the relay 64 fails to function as the power circuit voltage increases the horn 72 and light 76 will operate to give signals so as to alert the operator that trouble is present and he can proceed to correct the same.

While one embodiment of my invention has been shown and described, it will be apparent that other adaptations and modifications may be made without departing from the scope of the following claims.

I claim:

1. In apparatus including a driven member, a.D.C. motor, a drive spindle between said member and motor, and a DC. generator for supplying power to said motor, said generator having a field; the improvement comprising a switch mounted adjacent said spindle and operable by movement of said spindle out of its normal path, and means operable by actuation of said switch by said spindle to first remove power from the said generator field and then to apply reverse power voltage to said generator field whereby said motor is rapidly brought to a stop.

2. In apparatus including a driven member, a DC motor, a drive spindle between said member and motor, and a DC. generator for supplying power to said motor, said generator having a field; the improvement comprising a switch mounted adjacent each end of said spindle and operable by movement of said spindle out of its normal path, said switches being connected in series with each other to a power source, a circuit operable by actuation of either of said switches for removing power from the said generator field, and a second circuit operable after operation of first circuit to apply reverse power voltage to said generator field whereby said motor is rapidly brought to a stop.

7 3. In apparatus including a driven roll, a DC motor, a drive spindle between said roll and motor, and a DC. generator for supplying power to said motor, said generator having a field; the improvement comprising a bar pivotally mounted adjacent each end of said spindle in spaced relationship therewith, a switch operable by each of said bars when the spindle moves out of its normal path to contact the associated bar, said switches being connected in series with each other to a power source, a circuit operable by actuation of either of said switches for removing power from the said generator field, and a second circuit operable after operation of first circuit to apply reverse power voltage to said generator field whereby said motor is rapidly brought to a stop.

4. In apparatus including a driven top roll, a driven bottom roll, a DC. motor, a drive spindle between said top roll and said motor, a drive spindle between said bottom roll and said motor and a DC generator for supplying power to said motor, said generator having a field; the, improvement comprising a switch mounted adjacent each spindle and operable by movement of the associated spindle out of its normal path, said switches being connected in series with each. other to a power source, and means operable by actuation of either of said switches by its associated spindle to first remove power from the said generator field and after the generator voltage has decreased to a predetermined value to apply reverse power voltage to said generator field whereby said motor is rapidly brought to a stop.

5. In apparatus including a driven top roll, a driven bottom roll, a DC. motor, a drive spindle between said top roll and said motor, a drive spindle between said bottom roll and said motor and a DC. generator for supplying power to said motor, said generator having a field; the improvement comprising a switch mounted adjacent each end of each spindle and operable by movement of the associated spindle out of its normal path, said switches being connected in series with each other to a power source, a circuit operable by any of said switches for removing power from said generator field, and a second circuit operable after the generator voltage has decreased to a predetermined value to apply reverse power voltage to said generator field whereby said motor is rapidly brought to a stop.

6. In apparatus including a driven top roll, a driven bottom roll, a DC. motor, a drive spindle between said top roll and said motor, a drive spindle between said bottom roll and said motor and a DC. generator for supplying power to said motor, said generator having a field; the improvement comprising a bar pivotally mounted adjacent each end of each spindle in spaced relationship therewith, a switch operable by each of said bars when the spindle moves out of its normal path to contact the associated bar, said switches being connected in series with each other to a power source, a circuit operable by actuation of any of said switches for removing power from said generator field, and a'second circuit operable after the generator voltage has decreased to a predetermined value to apply reverse power voltage to said generator field whereby said motor is rapidly brought to a stop.

References Cited in the file of this patent UNITED STATES PATENTS Re. 15,733 Kesten et a]. Dec. 18, 1923 1,099,512 Palmer June 9, 1914 2,377,286 White May 29, 1945 2,642,557 Goldstein June 16, 1953 2,911,804 OBrien Nov. 10, 1959 

1. IN APPARATUS INCLUDING A DRIVEN MEMBER, A D.C. MOTOR, A DRIVE SPINDLE BETWEEN SAID MEMBER AND MOTOR, AND A D.C. GENERATOR FOR SUPPLYING POWER TO SAID MOTOR, SAID GENERATOR HAVING A FIELD; THE IMPROVEMENT COMPRISING A SWITCH MOUNTED ADJACENT SAID SPINDLE AND OPERABLE BY MOVEMENT OF SAID SPINDLE OUT OF ITS NORMAL PATH, AND MEANS OPERABLE BY ACTUATION OF SAID SWITCH BY SAID SPINDLE TO FIRST REMOVE POWER FROM THE SAID GENERATOR FIELD 